Automatic block signaling system



A ril 3, 1934. K EYER 1,953,718

AUTOMATIC BLOCK SIGNALING SYSTEM Filed April 28, 1932 2 Sheets-Sheet 1 A ril 3, 1934. K. MEYER AUTOMATIC BLOCK SIGNALING SYSTEM Filed April 28, 1952 2 Sheets-Sheet 2 Iigt.

D m w I H m m. WV W E TL 1 WV, #0 h D a n w. B m| if I 5 WW. u 2 S r 3 a AD M 4 T m 92/ Patented Apr. 3, 1934 AUTOMATIC BLOCK SIGNALING SYSTEM Karl Meyer, Berlin-Spandau, Germany, assignor to Orenstein & Koppel Aktiengesellschaft, Berlin, Germany Application April 28, 1932, Serial No. 608,060 In Germany September 25, 1931 5 Claims.

In automatic section-blocking installations it is desired that the rear signal should be dependent upon the regular changing of the forward signal. A signal set at stop cannot therefore change to line clear before the train has left the section and the advance signal has regularly changed to stop. Similarly the rear section should be able to recognize from its signal whether the advance signal is de-energized.

In most switching arrangements the block section is supplied through its two insulated running rails with low-tension alternating current, as a result of which, when the block section is unoccupied and intact, a relay connected either directly or through a special relay transformer attracts its armature and thereby controls corresponding line clear and stop circuits. In order to obtain the mutual interdependence of the individual block sections it has been proposed to influence the supply of current to the track in a rearward direction by means of a relay, the winding of which is excited by the signal lamp currents of the associated signal, so that in the event of the disappearance of the next signal indication the rear signal automatically changes to stop in consequence of the block relay armature falling off, as a result of which train protection is always possible.

These so-called supervising appliances with their movable parts are of course subjected to constant watching and inspection if they are to be effective, particularly as they are out of action in regular operation, but failures are not precluded. This disadvantage is obviated according to the present invention, the action being in other respects the same as in known systems.

The invention is illustrated in the accompanying drawings, in which Figures 1, 2, 3 and 4 are circuit diagrams representing four different forms in which the invention may be embodied.

According to the arrangement shown in Figure 1, by interposing in the common lead to the line clear signal lamp F and the stop signal lamp H the primary winding of a track feeding transformer B, its secondary winding, when the line clear or stop signal is alight, provides the rear block section with low-tension blocking current. The putting of a signal out of operation causes immediate interruption of the current in a rearward direction, this being effected without movable contacts, and as a result a change to stop immediately occurs at the rear, whereby the disturbance in the advance signal is indicated.

The voltages at the transformer B and the signal lamp F or H behave in the same way as the associated power outputs. Since the power to be transmitted in a rearward direction over the track by the transformer B, even taking into consideration all the losses that occur, is small in comparison with the power of the signal lamp, its primary voltage is also comparatively small. This becomes approximately zero, and the signal lamp voltage almost equal to the voltage of the mains, when a train is occupying the rear block section and short-circuits the two insulated running rails 21 and ii. The signal lamps then receive their normal rated voltage, whereas under other circumstances they burn at a lower voltage, the duration of their useful life being thereby prolonged.

The conditions in automatic block signaling, like those in manually operated signaling, involve the interdependence of the individual successive block sections. It is generally required by this interdependence that the change of a rear signal to line clear should only occur after a train has left the section, and only when the next signal, which covers the train, has regularly changed to stop. This is mostly obtained by sending over a special impulse conductor, in a rearward direction, an impulse current dependent upon the stop signal, the rear relay being thereby attracted, and the associated signal set to line clear. This solution, however, involves the provision of a special impulse conductor along the individual block sections. Apart from the increased expenditure on material and so forth hereby occasioned, failures arising from breakage of the conductor, short-circuits and so forth are not precluded, and provision also has to be made that the impulse of the advance stop signal must be made operative by further auxiliary means only when all the axles of the train have left the track section in question. These disadvantages are entirely obviated by the present invention.

If the interdependence of blocking is carried out as described above, the feeding of the rear section with current being effected through a track-feeding transformer the primary winding of which is traversed by the signal lamp currents of the forward section, an interdependence of signal sequence is obtainable in a simple manner according to this invention by providing the trackfeeding transformer with primary windings having different numbers of turns for the line clear and stop currents, or, more simply, by providing it with tappings on its primary winding, to which the signal circuits are connected.

According to Figure 2, the secondary winding 2'1 and 2'2. The primary winding of the transformer B is now connected to the signal circuits F and H in such a way that the line clear current flows through a smaller number of turns than the stop current. With equal or approximately equal signal currents, the voltage drops are then proportional to the squares of the numbers of turns, that is to say, when the line clear current is flowing, the track-voltage is less than when the stop current is flowing. The track voltages are proportional tot-he numbers of, turns of the primary winding for line clear and stop. By suitably selecting the numbers of turns the rear relay M will only attract its armature when the stop signal has appeared ahead, but will remain open if the line clear signal should not have disappeared ahead in consequence of a disturbance. When the changes back from stop to line clear, however, the relay armature is held fast even with thenow lower track voltage.

Inth-is-way the impulse conductor otherwise usual, along the block section is obviated, and a further advantage resides in the fact that the energization of the rear relay is effected by way of the track, and therefore only occurs when all 'the'axles. of the train have left the section.

In automatic block signaling, ordinary block relays are employed, which are connected directly or through av special relay transformer to the insulated track-and the armatures of which fall off as soon as a train occupies the block section and thereby short-circults the two insulated track rails. By special-provisions, such as impulse conductors and the like, the result is obtained that the armature only attracted again after. the stop signal appeared ahead, with a view to providing permanent protection for the train.

While for these purposes particularly sensitive and expensive relays have usually to be employed hitherto, in order to minimize the withdrawal of energy from the traclr while maintaining reliable.functioning, the present invent-ion proposes an arrangement in which ordinary electroemagnetic relays can be successfully employed. Thebasic idea consists in the fact t the track relay; not only attracts its armature with a minimum expenditure of energy but also holds the armature fast subsequently in a reliable manner even when the track voltage is greatly reduced, if the track voltage, hereinbefcre described, is dependent upon the condition of the advance signal indication, the possibility being thereby given of obtaining reliable interdependencewhile employing the simplest means.

The constants of the electromagnetic relay are not the same when the armature has fallen off as they are'when it is attracted. lhe difference is determined primarily by the air gap of the armature when it has fallen off. While the reactanceof the tension coil is comparatively small when'the. armature fallen off, it assumes very high values when the armature is attracted. A feature of the present invention consists in keeping this difference constant by connecting a higher or lower capacity in series with the tension coil, with its low or higher inductance when the armature has fallen off or is attracted, thus brin ing about as uniform a compensation as possible of the reactances under the different conditions. If this compensation is complete, the power consumption for attracting and holding the armature is a minimum. The alternating-current magnet then works exactly like a continuouscurrent magnet, which, when once attracted, holds its armature fast with a considerably diminished voltage.

In Figures 3 and 4, two constructional examples are indicated. The magnet M receives current'through a transformer A and the two insulated track rails 2'1 and is when the track-feeding transformer B is excited through one or another of .the primary tappings. Its reactance, which is at first low, is compensated by two condensersCar and C32 shown in Figure 3, which are connectedin parallel since the switch S2 is closed in a fallen condition. When the block relay Mattracts the armature its inductive reacstance changes to a definite limiting value, while by simultaneous opening of the contact S2 the supplementary condenser C32 is switched off, and the series capacity thereby brought to a value adapted to the inductance of the block relay M. Just as in the case of a continuous-current magnet, it is now possible to reduce the secondary voltage of the relay transformer A to a comparaively low value, the armature of the relay M still being held fast with sufficient attractive force.

For the purpose of attracting the armature of the relay M, as in the case of a continuous-current magnet, a definite voltage is necessary for the production of the requisite attractive force, and this voltage is delivered by the track-feeding transformer through the two insulated running rails when the signal H lights up and thereby provides a sufiiciently high track voltage in view of the larger number of energized turns of the track-feeding transformer B. If the stop signal H is extinguished by closing the contact S1, while at the same time the line clear signal F appears, the track voltage falls to a low value,

ing coil D3 in series with the relay M. The choking coil D3 is short-circuited when the relay armature is attracted, so that by this means compensation for the reactance is obtained both in a fallen-and in an attracted condition of the armature. rest of the arrangement is the same as before.

What I claim is:-

1. An automatic block signaling system for railways, with mutually interdependent sequence blocking, comprising a pair of insulated track rails divided into block sections, a static transformer for each section supplying electric current to the track rails, a line clear electric signal lamp at the beginning of each section, a

stop electric signal lamp at the beginning of each section, connected in parallel with the line clear signal lamp, means energized by the current in the track rails of each section for lighting up the line clear signal lamp at the beginning of that section, and a common conductor in series with both the signal lamps, the primary winding of the static transformer of each section being interposed in the common conductor of the signal lamps of the succeeding section, so

that in the event of the current through the sig- "1' The functioning, with respect to the nal lamps of a section being interrupted the supply of current to the track rails of the preceding section ceases, and the signal at the beginning of the said preceding section is thereby changed to stop.

2. An automatic block signaling system for railways, with mutually interdependent sequence blocking, comprising a pair of insulated track rails divided into block sections, a static transformer for each section supplying electric current to the track rails, a line clear electric signal lamp at the beginning of each section, a stop electric signal lamp at the beginning of each section, connected in parallel with the line clear signal lamp and a relay energized by the current in the track rails of each section, the armature of the relay being adapted when attracted to light up the line clear signal lamp at the beginning of that section, each of the lamps of a section being so connected with the primary winding of the transformer that supplies current to the rails of the preceding section that the voltage impressed by the transformer upon the rails of a section when the stop lamp of the succeeding section is alight is sufiicient to cause the relay to attract its armature, whereas the voltage impressed by the transformer upon the rails when the line clear lamp of the succeeding section is alight is only sufficient to hold the armature if already attracted but not surficient to attract it.

3. An automatic block signaling system for railways, with mutually interdependent sequence blocking, comprising a pair of insulated track rails divided into block sections, a static transformer for each section supplying electric current to the track rails, a line clear electric signal lamp at the beginning of each section, a stop electric signal lamp at the beginning of each section, connected in parallel with the line clear" signal lamp, a relay energized by the current in the track rails of each section, the armature of the relay being adapted when attracted to light up the line clear signal lamp at the beginning of that section, each of the maps of a section being so connected with the primary winding of the transformer that supplies current to the rails of the preceding section that a current flowing through the stop lamp traverses a larger number of turns of the primary winding than a current flowing through the line clear lamp, the respective numbers of turns being so adjusted that the voltage impressed by the transformer upon the rails of a section when the stop lamp of the succeeding section is alight is sufficient to cause the relay to attract its armature, whereas the voltage impressed by the transformer upon the rails when the line clear lamp of the succeeding section is alight is only suflicient to hold the armature if already attracted but not sufiicient to attract it.

4. An automatic block signaling system as claimed in claim 2, further comprising a variable reactance connected in series with the relay coil, means for automatically varying the reactance according to the condition of the relay in such a way that whether the relay armature is attracted or not the reactance will always be substantially in resonance with the impedance of the relay coil.

5. An automatic block signaling system as claimed in claim 2, further comprising a reactance adapted to be connected in series with the relay coil, the value of the reactance being such as to produce a state of resonance with the relay coil when the relay armature is not attracted, a second reactance adapted to be connected in series with the relay coil, the value of the second reactance being such as to produce a state of resonance with the relay coil when the relay armature is attracted, and a switch, actuated by the relay itself, adapted to connect the first reactance with the relay coil when the armature is not attracted and to connect the second reactance with the relay coil when the armature is attracted.

KARL MEYER. 

